Income Taxes	3 Months Ended
Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three months ended March 31, 2020 and 2019, the Company recorded income tax expense of $0.8 million and less than $0.1 million, respectively. The income tax expense for the three months ended March 31, 2020 was primarily driven by the estimated effective tax rate for the year and the discrete impact of $0.4 million of net shortfall tax expense related to stock-based compensation activity during the quarter. As a result of the tax valuation allowance against deferred tax assets in the U.S., there was no benefit for federal income taxes associated with the loss before taxes for the three months ended March 31, 2019. Income taxes were recorded related to certain U.S. state and foreign jurisdictions for the three months ended March 31, 2019. The Company assesses the need for a valuation allowance against its deferred tax asset each quarter through the review of all available positive and negative evidence. Deferred tax assets are reduced by a tax valuation allowance when, in the opinion of management, it is more likely than not that some portion of the deferred tax assets will not be realized. The analysis depends on historical and projected taxable income. Projected taxable income includes significant assumptions related to revenue, commercial expenses and research and development activities. During the third quarter of 2019, after considering all available positive and negative evidence, including but not limited to cumulative income in recent periods, historical, current and future projected results and significant risks and uncertainties related to forecasts, the Company concluded that it was more likely than not that substantially all of its deferred tax assets in the U.S. are realizable in future periods. A valuation allowance was retained against certain U.S. federal tax attributes with short carryforward periods and District of Columbia state deferred tax assets as of March 31, 2020 and December 31, 2019.

Income Taxes

3 Months Ended

Mar. 31, 2020

For the three months ended March 31, 2020 and 2019, the Company recorded income tax expense of $0.8 million and less than $0.1 million, respectively. The income tax expense for the three months ended March 31, 2020 was primarily driven by the estimated effective tax rate for the year and the discrete impact of $0.4 million of net shortfall tax expense related to stock-based compensation activity during the quarter. As a result of the tax valuation allowance against deferred tax assets in the U.S., there was no benefit for federal income taxes associated with the loss before taxes for the three months ended March 31, 2019. Income taxes were recorded related to certain U.S. state and foreign jurisdictions for the three months ended March 31, 2019.

The Company assesses the need for a valuation allowance against its deferred tax asset each quarter through the review of all available positive and negative evidence. Deferred tax assets are reduced by a tax valuation allowance when, in the opinion of management, it is more likely than not that some portion of the deferred tax assets will not be realized. The analysis depends on historical and projected taxable income. Projected taxable income includes significant assumptions related to revenue, commercial expenses and research and development activities. During the third quarter of 2019, after considering all available positive and negative evidence, including but not limited to cumulative income in recent periods, historical, current and future projected results and significant risks and uncertainties related to forecasts, the Company concluded that it was more likely than not that substantially all of its deferred tax assets in the U.S. are realizable in future periods. A valuation allowance was retained against certain U.S. federal tax attributes with short carryforward periods and District of Columbia state deferred tax assets as of March 31, 2020 and December 31, 2019.